I've implemented the google service barcode detector in my android app,some time ago. (part of the Mobile vision API). Untill now everything worked well. All of my customers are using a code_39 barcode type, and all of them have only numbers in their barcode values.

Recently, a new customer of mine started using the app - the problem is that he has also letters in his barcode stickers. For example:

m-108

For some reason, the barcodeDetector detects it as

+M-108

even when I tried defining the barcode type specifically (instead of Barcode.ALL_FORMATS)

        barcodeDetector = new BarcodeDetector.Builder(this)
                .setBarcodeFormats(Barcode.CODE_39)
                .build();

It still doesn't recognize the barcode correctly (adding the plus sign, and reading lowercased m as uppercased m)

I tried to search this issue forever now, but couldn't find any clue.

I know that there are two types of code_39 - one of the is full ascii (which apreantly is my customer's using), but I can't find a way to define the barcodeDetector to treat it as full-ascii.